Double ended infrared (IR) halogen lamps generally comprise a quartz tube, a tungsten filament, and a fill gas comprising an inert gas such as xenon and at least one halogen gas. Such lamps require a well defined shaped bulb and a precisely aligned filament in order to achieve maximum efficiency of infrared energy collection. FIGS. 1A-B depict a known halogen lamp 107. Referring to FIG. 1A, a lamp body 102 is formed from a quartz tube 104 having an inside (inner) diameter ID and an outside (outer) diameter OD. A light emitting chamber 106 (bulb) is formed using techniques known to one of ordinary skill in the art. A chamber 106 has an exterior coating (not shown). As shown in FIG. 1B, a filament 110, which may be a tungsten filament, is positioned within the lamp body 102, with a coiled portion positioned within the chamber 106. Spuds 112a-b align the filament 110 on a longitudinal axis of the lamp body. FIG. 1B shows sealed portions 114a-b that result from sealing the end portions 108a-b after positioning the filament 110 within the lamp body.
The outer surface of the chamber 106 is coated with a multilayer film (not shown) that transmits visible radiation (visible light) and reflects IR radiation back to the filament 110. Such a film is described in, e.g., U.S. Pat. No. 6,476,556, by Cottaar. The reflected IR energy is reabsorbed by filament 110 to decrease the power required to operate the lamp 107 without reducing the visible radiation output, thus improving efficiency. The amount of reabsorbed IR energy is highly dependent on the radial alignment of the filament 110 along the longitudinal axis of the lamp 107. Reflected energy that misses the filament 110 and is not reabsorbed eventually leaks through the end portions 114a-b. Such end losses do not contribute to the conversion of IR energy to visible radiation.